Electric fuses are generally provided with blown fuse indicators in the form of a spring-biased indicating pin, normally held in position by a restraining wire, and allowed to move to a blown fuse indicating position in response to blowing of the fuse and subsequent melting of the restraining wire. Generally blown fuse indicating pins are arranged at one of the end surfaces of the fuse. Since the space available at this location is relatively limited, the pins are generally of small size. This fact combined with the fact that the end surfaces of fuses are generally much less exposed to view than the lateral surfaces thereof, imposes serious limitations on the usefulness of blown fuse indicators of the aforementioned conventional type.
In an effort to achieve a more conspicuous indication of whether or not a fuse has blown, blown fuse indicators have been arranged at the lateral surfaces of fuses, or their casings, respectively. This arangement greatly facilitates the supervision and maintenance of fuse-protected electric distribution systems, but requires the provision of a perforation or hole in the lateral wall of the casing of such fuses, which impairs the mechanical integrity of the casing.
It is, therefore, one of the prime objects of this invention, to provide highly visible or conspicuous blown fuse indicating means on the lateral surfaces of the casings of electric fuses, without any impairment of the mechanical integrity of the casings.
Another object of the invention is to provide means allowing to convert electric fuses having conventional relatively small and inconspicuous blown fuse indicator pins on one of the end surfaces thereof into fuses having relatively large and conspicuous blown fuse indictor pins on the lateral surfaces thereof.
Other objects and advantages of the invention will become apparent as this specification proceeds.